Acknowledgments
The authors are grateful to Conselho Nacional de
Desenvolvimento Científico e Tecnológico (CNPq), a Brazilian government
agency for the advancement of science. Research scholarships
were granted by CNPq to Marcelo K. Lenzi, Marcos L. Corazza
and Eduarda M. Bainy by Coordenação de Aperfeiçoamento de
Pessoal de Nível Superior (CAPES), a Brazilian government agency
for the development of personnel in higher education.